[Therion] 3d to QGIS - different alignment

[Bill Gee]

Hi Andrew -

What a coincidence this is!  I have been struggling with QGIS for a 
couple of weeks.  It has a VERY steep learning curve.  I am beginning to 
think that our future as cave cartographers will include some kind of 
GIS work.  Some sort of tutorial would be very useful for complete GIS 
newbies like me

I got your Survex plugin loaded.  That was easy.  It will open and view 
a .3d file which is produced by Therion.  QGIS shows centerline and 
survey stations, but no walls.  Nothing from LRUD.  I suspect that 
Therion does not create the same kind of file as Survex.  Viewing the 
file in Aven also does not show any kind of walls or passage polygons.

I have struggled to get some sort of DEM file.  That is another learning 
curve!  I have a GeoTIFF file which covers several square miles around 
the current cave project.  The web site I got it from (USGS) would not 
zoom in any further.  I was able to add another layer which is the .shp 
file from Therion's ESRI output.  Also a .kml file.  Neither the .shp 
nor the .kml file is visible

This cave runs directly under the owner's house.  We would very much 
like to see some sort of 3D view which shows how the cave and surface 
are related.  I suspect there is only 20 feet or so between the house 
and the cave.  Not much!  The owner has some ideas for renovation which 
would reduce that, possibly to something that is not safe.


===============
Bill Gee

On 2/20/25 05:57, Andrew Atkinson wrote:
> Hi all
> 
> Not strictly a Therion question, but the answer is likely to be in the 
> data entry or the interpretation of data in Therion.
> 
> I'm slowly incorporating QGIS into my workflow, and trying to automate it.
> 
> As such I'm using a modified version of the survex 3d importer
> 
> https://github.com/AndrewAkinson/qgis3-survex-import_amend
> 
> So that items can be easily switched on and off I'm going down the line 
> of importing the 3d files by cave rather than the generated one for the 
> whole catchment
> 
> For now I'm doing it with the data in
> http://www.cave-registry.org.uk/svn/CheddarCatchment/
> 
> Currently I'm working on the Longwood Valley area as Longwood Valley 
> Sink has been recently discovered.
> 
> The directories I'm using
> 
> RRift/ (3d needs to be generated from survex)
> LongwoodValleySink/
> Longwood/ (Fake data with calibrate compass -90!)
> Toothache/ (single leg)
> 
> In each of these directories the .th file generates a survex 3d file
> 
> Also in the the root there is a LongwoodValley.thcfg which has the above 
> caves (plus maybe Charterhouse, GB, TynningsGS and Reads depending on 
> how I left it)
> 
> In the diagram attached (hopefully this list does attachments!)
> 
> The Dark purple dots are the import of the 3d file that has Rhino, 
> Longwood, LongwoodValley Sink and Toothache together. The light pink, 
> yellow dots are the individual imports (and entrances from the MCRA 
> database.) Also included is an overlay of a scree shot from aven, which 
> agrees with the group import.
> 
> The question is why is Longwood different when imported as a 3d on its 
> own compared with as a group? They are both using the same data!
> 
> Andrew
> 
> _______________________________________________
> Therion mailing list
> Therion at speleo.sk
> https://mailman.speleo.sk/listinfo/therion